Which ruler commissioned the Hagia Sophia in Constantinople?

Justinian I commissioned the Hagia Sophia in Constantinople.

The Byzantine emperor Justinian I ordered the present Hagia Sophia after riots destroyed an earlier church during the Nika revolt of 532. Architects Anthemius of Tralles and Isidore of Miletus designed the new building, which was completed in 537.

The church served as the cathedral of Constantinople and became the principal church of the Byzantine Empire. Its vast dome, innovative engineering, and interior decoration made it one of late antiquity's most influential buildings. The structure was repaired and modified after earthquakes and later damage.

Hagia Sophia became a mosque after the Ottoman conquest of Constantinople in 1453. It was converted into a museum in 1935 and redesignated as a mosque in 2020. Constantine the Great is sometimes associated with the site because he founded Constantinople and an earlier church stood there, but he did not commission the current sixth-century building.